As one type of CSP (Chip Scale/Size Package) semiconductor device is known the construction in which a semiconductor chip is mounted face down on a substrate (flip-chip connection).
In this case, between the semiconductor chip and the substrate a resin is commonly provide as an underfill material. The resin is provided by being injected between the semiconductor chip and the substrate after mounting, or by being previously applied to the substrate before mounting. However, the step of providing the resin entails an extra process, and makes the manufacturing process of the semiconductor device correspondingly longer.
Moreover, with the development of multi-chip modules in recent years, the configuration of mounting semiconductor chips on both surfaces of a wiring substrate has been developed. However, for this purpose, interconnecting lines must be formed on both surfaces of a substrate, and further for electrical conduction between the interconnecting lines on both surfaces via holes are required, resulting in increased costs and degraded manufacturing processes.